It is supposed that usually the texts were written in ordinarybooks first, then transferred to blank linkable books later when
finished, in order to prevent the problem of running out of space.

It is very important to not write contradictions into your
descriptive books; writing contradictions in would link to an
unstableAge -- after a while (or maybe before a while, depending
on the nature of the contradiction) the Age would start to fall
apart. Beginner Writers (seltahntee) had this taught to them
relentlessly from the start. It is possible to make changes to an
Age by writing new text into the descriptive book; if the parameters
changed had not yet been observed by anyone and/or the change was
small enough, the new specifications would actually affect the Age
to which the book linked; however, if the parameters had been observed
and/or the changes were too large, the book's link would shift over
to a different Age, though any linking books would still point to
the original Age.